No Garlic Benefits Seen in Heart Trial

By LAWRENCE K. ALTMAN

Published: December 25, 1996

THE suggestion that garlic has protective effects against heart disease has been challenged by a study in England that found that a powdered form of the clove was no better than a dummy pill in lowering cholesterol and fats in the blood.

Earlier studies had suggested several benefits of ''the stinking bulb'' in protecting against heart disease and heart attacks. One is to reduce the level of cholesterol and other lipids, or fats, in the blood. A second is to block the action of platelets, the tiny fragments that help blood clot. A third is to enhance the activity of antioxidants.

But studies suggesting the lipid-lowering benefits have been criticized for flaws in the way they were carried out, and experts have called for better controlled studies to clearly delineate garlic's cardiovascular benefits.

So a team of nine scientists in England did what they described as a rigorous two-part study. One was a scientifically controlled study of 115 participants. The other was a type of statistical review of other studies known as a meta-analysis.

The study tested the effects of garlic on 115 participants from 35 to 64 years old who had not been able to lower their lipids sufficiently through diet. The group had high total cholesterol levels, ranging from 232 to 329 milligrams per deciliter. They also had low-density lipoprotein levels of 135 or higher, which is above the desirable level.

The 115 participants were split into two smaller units. One took an odor-controlled Kwai dried garlic tablet three times a day for six months. The other unit took a pill that was similar in appearance but that contained lactose, a sugar, but no garlic. Neither the participants nor their doctors knew the contents of the pills.

No statistically significant differences were found between the two groups in terms of the level of lipids in their blood, the team headed by Dr. H. A. W. Neil of the University of Oxford reported earlier this year in The Journal of the Royal College of Physicians of London.

Dr. Neil's team said its findings were consistent with a smaller study reported last year in which garlic also failed to lower the level of lipids in the blood

The scientists included their new study in the statistical review. They found a cholesterol-level drop of 25, which was less of a reduction than earlier meta-analyses had found. The researchers also pointed to shortcomings in the original studies as one explanation for this apparent reduction.